The present invention generally relates to the conversion of chemical energy to electrical energy. More particularly, the present invention relates to predicting or modeling the discharge performance of an alkali metal electrochemical cell having a carbonaceous cathode active material, such as of a Li/CFx couple. Every Li/CFx cell has a voltage capacity signature and as the cell is discharged, the relationship between the cell life or depth-of-discharge and voltage (mV) changes. Therefore, it is desirable to predict or model this signature prior to building a cell. This modeling is predicated on an estimation of the depth of discharge versus voltage relationship for the CFx cell.